1. Field of the Invention
This invention relates to tension bridles for a cold rolling mill that reduces the thickness of a metal strip as the metal strip is passed through the rolling mill. The tension bridles create increased tension in the strip at the reducing stand following the bridle so that an increased reduction in thickness of the metal strip can be obtained than would ordinarily be the case without the tension bridle. The invention is also applicable to reversing cold rolling mills whereby a tension bridle is positioned at each end of the reversing mill. By placing a tension bridle after the final reducing stand, increased tension can be placed on the strip to cause an increased reduction in thickness of the strip in the final stand. The higher tension on the final reducing stand will improve the strip gauge and shape without any detrimental effect on the end product. The use of the exit bridle will also reduce tension on the coiler reels which reduces coil quality problems.
2. Description of the Prior Art
Cold rolling mills for reducing the thickness of metal strip products are well known. Cold rolling mills are utilized in many industries such as the rolling of steel, aluminum, and other nonferrous metals. In the typical steel cold rolling mill, a series of reducing stands containing reducing rolls are utilized to gradually reduce the initial thickness of the strip steel entering the first stand by passing the strip steel between opposed rolls which reduce its thickness.
Cold rolling mills that are reversible are also well known in the art and in such mills, a strip of metal is passed in one direction through one or more reducing stands and the strip is coiled after the first pass through the mill. The strip is then reversed in direction and passes through the stands a second time to achieve further reduction of the thickness of the metal strip. Upon passing through the reducing stands a second time, the metal strip is again coiled. The metal strip can be passed through the reducing stands three, four or more times to achieve the level of reduction desired in the finished product.
A tension bridle of the type disclosed in this Specification has not been used to increase the tension on the reducing stands of a cold rolling mill at both the entry end and the exit end of the mill. The tension bridle of the present invention, by increasing the tension of the strip between the bridle and the reducing stand allows a significant increase in reduction in thickness to take place within each reducing stand that the bridle operates on than would be possible without the tension bridle.